On Wed, May 23, 2018 at 09:39:28AM +0800, Jason Wang wrote:
>
>
> On 2018年05月23日 00:54, Wei Xu wrote:
> >On Wed, May 16, 2018 at 08:32:20PM +0800, Jason Wang wrote:
> >>Signed-off-by: Jason Wang <jasow...@redhat.com>
> >>---
> >> drivers/vhost/net.c | 3 +-
> >> drivers/vhost/vhost.c | 539
> >> ++++++++++++++++++++++++++++++++++++++++++++++----
> >> drivers/vhost/vhost.h | 8 +-
> >> 3 files changed, 513 insertions(+), 37 deletions(-)
> >>
> >>diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> >>index 8304c30..f2a0f5b 100644
> >>--- a/drivers/vhost/vhost.c
> >>+++ b/drivers/vhost/vhost.c
> >>@@ -1358,6 +1382,8 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned
> >>int ioctl, void __user *arg
> >> break;
> >> }
> >> vq->last_avail_idx = s.num;
> >>+ if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
> >>+ vq->avail_wrap_counter = s.num >> 31;
> >> /* Forget the cached index value. */
> >> vq->avail_idx = vq->last_avail_idx;
> >> break;
> >>@@ -1366,6 +1392,8 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned
> >>int ioctl, void __user *arg
> >> s.num = vq->last_avail_idx;
> >> if (copy_to_user(argp, &s, sizeof s))
> >> r = -EFAULT;
> >>+ if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
> >>+ s.num |= vq->avail_wrap_counter << 31;
> >> break;
> >> case VHOST_SET_VRING_ADDR:
> >> if (copy_from_user(&a, argp, sizeof a)) {
> >'last_used_idx' also needs to be saved/restored here.
> >
> >I have figured out the root cause of broken device after reloading
> >'virtio-net' module, all indices have been reset for a reloading but
> >'last_used_idx' is not properly reset in this case. This confuses
> >handle_rx()/tx().
> >
> >Wei
> >
>
> Good catch, so we probably need a new ioctl to sync between qemu and vhost.
>
> Something like VHOST_SET/GET_USED_BASE.
Sure, or can we expand 'vhost_vring_state' to keep them done in a bunch?
>
> Thanks
>
